In order to allow users to type annotate fixtures they request, the
types need to be imported from the `pytest` namespace. They are/were
always available to import from the `_pytest` namespace, but that is
not guaranteed to be stable.
These types are only exported for the purpose of typing. Specifically,
the following are *not* public:
- Construction (`__init__`)
- Subclassing
- staticmethods and classmethods
We try to combat them being used anyway by:
- Marking the classes as `@final` when possible (already done).
- Not documenting private stuff in the API Reference.
- Using `_`-prefixed names or marking as `:meta private:` for private
stuff.
- Adding a keyword-only `_ispytest=False` to private constructors,
warning if False, and changing pytest itself to pass True. In the
future it will (hopefully) become a hard error.
Hopefully that will be enough.
Mypy currently is unable to handle assigning attributes on function:
https://github.com/python/mypy/issues/2087.
pytest uses this for the outcome exceptions -- `pytest.fail.Exception`,
`pytest.exit.Exception` etc, and this is the canonical name by which they
are referred.
Initially we started working around this with type: ignores, and later
by switching e.g. `pytest.fail.Exception` with the direct exception
`Failed`. But this causes a lot of churn and is not as nice. And I also
found that some code relies on it, in skipping.py:
def pytest_configure(config):
if config.option.runxfail:
# yay a hack
import pytest
old = pytest.xfail
config._cleanup.append(lambda: setattr(pytest, "xfail", old))
def nop(*args, **kwargs):
pass
nop.Exception = xfail.Exception
setattr(pytest, "xfail", nop)
...
So it seems better to support it. Use a hack to make it work. The rest
of the commit rolls back all of the workarounds we added up to now.
`pytest.raises.Exception` also exists, but it's not used much so I kept
it as-is for now.
Hopefully in the future mypy supports this and this ugliness can be
removed.
This reverts commit dfe54cd82f.
The idea in the commit was to simplify the code by removing the check
and instead letting it TypeError which has the same effect.
However this type error is caught by mypy, and rather than ignoring the
error we think it's better and clearer to go back to the previous
explicit check.
It doesn't seem to add much value (why would one execute tests
based on that marker?), plus using the docstring for that
encourages one to write a more descriptive message about the test
In previous Python versions, the list of warnigns appears like:
... list of emitted warnings is: [UserWarning('user',)].
In Python 3.7 apparently the string representation has been improved to:
... list of emitted warnings is: [UserWarning('user')].
Fix#3011
Zac Hatfield-Dodds
Lesnek
Cheukting
Reagan Lee
Ronny Pfannschmidt
Anthony Sottile
Ran Benita
Florian Bruhin
Bruno Oliveira
Olga Matoula
Garvit Shubham
Ran Benita
Ronny Pfannschmidt
Ankit Goel
Jeffrey Rackauckas
Joan Massich
Andras Tim